Files
Syplheed-Reborn/docs/re
Claude (auto-RE) 3d3d6726fa re(flight): START skips the briefing, and the player-entity lock is stage-specific
The scripted route now reaches FLIGHT unattended: boot -> main menu -> poke the
cleared-stage mask -> EXTRAS -> MISSION SELECT -> stage -> briefing -> READY ROOM
-> TAKE OFF -> flight, verified by a full HUD (TIME 00:52.54, speed 350, shields,
REMAINING OB 018) on stage 01.

Two things that cost a run each:

START skips the briefing; A does not. A pages through the brief, and ten A taps
still left the run sitting on a briefing screen -- twice, on two different
stages. One START press lands on the READY ROOM. fly_stage.sh now presses START.

entities2.py's `self` locked on `"Player" in name`, and that suffix is
STAGE-SPECIFIC: stage 02 fields UN_f002_TCAF_DeltaSaber_W_Player, but stage 01
fields UN_f001_TCAF_DeltaSaber_T with no suffix, so the filter found nothing
while the game was visibly flying and reporting 64 typed live entities. Falls
back to the craft class and prefers the instance that is actually moving (a
mission holds more than one). Recorded rather than worked around, because the
same assumption is embedded in several probes.
2026-08-13 21:45:54 +00:00
..

Reverse-engineering knowledge base

This directory is the spec-side of the clean-room: it records what the original Project Sylpheed binary does (behaviour) and how its data is laid out, so that the Rust port can be implemented from these specs without re-deriving anything and without ever copying original code.

It exists to answer one question fast: "do we already know how X works, and how sure are we?"


The one rule that matters

Never document a claim more confidently than the evidence supports, and never paste original code here.

A wrong-but-confident note is worse than no note: someone builds on it and the bug hides for weeks. Every entry therefore carries an explicit confidence and its evidence. This mirrors the project method — measure the oracle, never infer; refute before believing.

Clean-room firewall

  • Allowed: behaviour descriptions, field offsets/types, formulas, state machines, observed input→output pairs, and references to the original by address (sub_821B68C0) or to xenia-rs/sylpheed.db.
  • Forbidden here and in crates/: pasted decompiled C/C++ or verbatim disassembled function bodies presented as the thing to reimplement. Cite the address; describe the behaviour in your own words. Disassembly is a tool for understanding, not a source to copy.

Confidence levels

Level Meaning Bar to reach it
CONFIRMED Behaviour verified against ground truth. ≥2 independent observations or one observation cross-checked against an oracle (canary framebuffer, a known-correct value, a second code path).
PROBABLE Strong single-source inference. One clean observation, or an unambiguous static read of the disassembly.
HYPOTHESIS Educated guess, not yet tested. Anything else. Must say what would confirm/refute it.

Promotion requires new evidence, not re-reading the old evidence. A HYPOTHESIS that "looks right again" is still a HYPOTHESIS. Only an independent check promotes it. If evidence later contradicts an entry, demote it and record the contradiction — do not silently edit the conclusion.


When to document

  • Right after a function/structure crosses from HYPOTHESIS to at least PROBABLE — before moving to the next code path, so the knowledge isn't lost or re-derived.
  • Whenever confidence changes (up or down) — append to the Evidence log, don't overwrite.
  • Not while it's still a pure guess with no evidence — a one-liner in the relevant backlog/plan is enough until there's something to stand on.

What to document

  • Functions/code pathsdocs/re/functions/<name>.md (one file per function or tight cluster).
  • Data structures / formatsdocs/re/structures/<name>.md.
  • Keep the index in INDEX.md (one line each: name · confidence · one-line summary).

Use the templates: _TEMPLATE.function.md, _TEMPLATE.structure.md.


How we find and confirm code paths (the toolchain)

Everything joins on the guest virtual address (PC) — code addresses are fixed by the XEX load, identical across our emulator and canary.

  • Static (cheap, try first): xenia-rs/sylpheed.db (DuckDB: 25 481 functions, xrefs, strings, vtables, imports). Query with xenia-rs/zq.pyzq.py grep <str>, zq.py xref <addr>, zq.py dis <lo> <hi>, zq.py fn <pc>. Entry points are usually a string (zq.py grep MSG_DEMO) or an import (movie/XMA API) xref'd back to the loader.
  • Dynamic (when static is ambiguous): run xenia-rs with its probe suite — --pc-probe / --audit-pc-probe-hex (fires at block entry), --mem-watch (mid-block reads/writes of a VA), --lr-trace (call/return chains), --trace-instructions, --dump-addr (read guest memory). These already exist; prefer them over hacking canary.
  • Oracle (correctness ground truth): canary — the Wine cross-build xenia-canary/build-cross/bin/Windows/Debug/xenia_canary.exe (the native Linux ELF crashes / does not run — do not use it). This is the only emulator that reaches the in-game menu; our xenia-rs never got past the intro video. Use canary to observe output (capture its framebuffer for texture colours), not usually to instrument code — though its build-cross toolchain does compile, so small C++ probes + rebuild are possible when needed. Run muted, one emulator process at a time, point it at the real ISO (not the symlink).

⚠️ VA-equality caveat: join code by PC (fixed), but never assume a data VA holds the same bytes across emulators — allocators differ. Compare data by content/layout.